Etching solution composition for adjusting etching selectivity of titanium nitride film to tungsten film and etching method using the same

Abstract

The present invention relates to an etching composition capable of adjusting the etching selectivity of a titanium nitride film to a tungsten film and an etching method using the same. The etching composition includes an inorganic acid, an oxidizing agent, an additive represented by Chemical Formula 1, and the balance of water, and exhibits the following remarkable effects: according to various wet etching processes of semiconductor manufacturing processes, the etching rate of the titanium nitride film can be maintained significantly faster, and at the same time, the etching selectivity of the titanium nitride film to the tungsten film can be adjusted to 1 to 15 for use.

Description

Technical Field

[0001] The present invention relates to a composition capable of adjusting the etching selectivity of a metal nitride film to a metal film in a process of manufacturing a semiconductor device, and an etching method using the composition. In particular, the present invention relates to an etching liquid composition capable of adjusting the etching selectivity of a titanium nitride film to a tungsten film, and an etching method using the composition. Background Art

[0002] In a semiconductor manufacturing process, a tungsten film is used for filling a gate electrode, a wiring, a barrier layer, or a contact hole or via hole of a thin film transistor of a semiconductor device and a liquid crystal display.

[0003] In addition, a titanium nitride film is used as a base layer and a covering layer of a noble metal or aluminum or copper wiring of a printed wiring board, a semiconductor device, a liquid crystal display, etc., and sometimes used as a barrier layer metal or a gate metal.

[0004] In a semiconductor manufacturing process, the tungsten film is widely used as a conductive metal. However, since the adhesion of the tungsten film to other films such as a silicon film and a silicon oxide film is poor, the titanium nitride film is mainly used as a protective film for the tungsten film.

[0005] In a semiconductor manufacturing process, as a process for removing these films, a dry etching process and a wet etching process are often used together. In the case of a tungsten film, a CMP process is sometimes used. At this time, for a process having an etching selectivity capable of etching a specific portion of a titanium nitride film and a tungsten film at the same speed or etching the two films at different speeds, it is difficult to achieve by a dry etching process. Therefore, a wet etching process is required. For this reason, in reality, an etching liquid composition suitable for these wet etching processes is required.

[0006] Korean Patent Publication No. 10-2015-050278 discloses an etching liquid composition for a laminate of a titanium nitride film and a tungsten film, in which the etching rates of the titanium nitride film and the tungsten film are the same, so that the etching selectivity of the titanium nitride film to the tungsten film is 1, and as a high-temperature process, it includes a technology capable of being used for a long time in a batch process.

[0007] However, recently, the wet etching process in a semiconductor process is being changed to a single-type process that is advantageous in preventing recontamination of particles in the process. Compared with a batch process that requires a process time of several tens of minutes, the single-type process has an advantage of completing the process within several minutes. Therefore, in reality, the case of performing an etching process in a single-type is increasing.

[0008] In addition, in the case of using such a single-type etching process, in reality, it is necessary to develop an etching liquid composition in which the etching rate of the titanium nitride film is much faster than that of the tungsten film, that is, an etching liquid composition having a high etching selectivity of the titanium nitride film to the tungsten film.

[0009] On the other hand, from the perspective of the type of memory, in the case of NAND flash memory, an etching liquid with the same etching rate for the tungsten film and the titanium oxide film is required, that is, an etching liquid with an etching selectivity of the titanium oxide film to the tungsten film of 1 is required. In contrast, in the case of DRAM, an etching liquid with a faster etching rate of the titanium nitride film than the tungsten film is required, that is, an etching liquid with a high etching selectivity of titanium nitride to tungsten film is required. Therefore, ultimately, in reality, there is an urgent need to develop an etching liquid composition whose etching selectivity can be adjusted from 1 to a high selectivity. Summary of the Invention

[0010] (Technical Problems to be Solved)

[0011] The present invention aims to solve the above-mentioned problems, and its purpose is to provide an etching liquid composition that can maintain the etching rate of the titanium nitride film significantly faster while being able to adjust the etching selectivity of the titanium nitride film to the tungsten film in the range of 1 to a high selectivity when performing various wet etching processes on the tungsten film and the titanium nitride film in a single type.

[0012] Another object of the present invention is to provide an etching method using such an etching liquid composition.

[0013] (Solutions to the Problems)

[0014] According to the etching composition of the present invention, as an etching liquid composition comprising an inorganic acid, an oxidizing agent, an additive represented by Chemical Formula 1, and the balance of water, it is an etching liquid composition that can maintain the etching rate of the titanium nitride film significantly faster and at the same time can adjust the etching selectivity of the titanium nitride film to the tungsten film in the range of 1 to a high selectivity.

[0015] The inorganic acid contained in the etching liquid composition of the present invention can be any one selected from the group consisting of sulfuric acid, phosphoric acid, and mixtures thereof as an etching accelerator.

[0016] Among them, the content of the inorganic acid can be 81 to 95% by weight based on the total weight of the etching liquid composition.

[0017] In addition, the oxidizing agent contained in the etching liquid composition of the present invention can be any one selected from the group consisting of hydrogen peroxide, nitric acid, tert-butyl hydroperoxide, and 2-butane peroxide.

[0018] At this time, relative to the total weight of the etching liquid composition, the content of the oxidizing agent may be 0.1 to 3% by weight.

[0019] In addition, the additive contained in the etching liquid composition of the present invention is represented by the following Chemical Formula 1, and may include an alkylammonium salt or an alkylalkanolammonium salt containing a cationic surfactant, and may include an alkyl sulfate containing an anionic surfactant.

[0020] Among them, relative to the total weight of the etching liquid composition, the content of the additive represented by Chemical Formula 1 may be 20 to 500 ppm by weight.

[0021]

Chemical Formula 1

[0022]

[0023] In the above Chemical Formula 1, R1, R2, R3 and R4 may independently be a hydrogen atom, an alkyl group having 1 to 18 carbon atoms, a benzylalkyl group having 1 to 20 carbon atoms or an alkyl alcohol group having 1 to 6 carbon atoms, R5 is 1 / 2 oxygen atom, a hydroxyl group, an alkyl group having 1 to 16 carbon atoms, and n is 1 to 2.

[0024] The etching liquid composition can adjust the composition components and composition ratios of the composition, so that it can maintain the etching rate of the titanium nitride film significantly faster, and at the same time can adjust the etching selectivity of the titanium nitride film to the tungsten film. In particular, the structures of the cation and anion of the additive represented by Chemical Formula 1 can be adjusted. Accordingly, the etching selectivity of the titanium nitride film to the tungsten film can be adjusted to 1 to 15 (etching amount of titanium nitride film: etching amount of tungsten film = 1:1 to 15:1).

[0025] The etching process temperature of the etching liquid composition may be 50°C to 90°C. In order to improve the stability of the etching process, the inorganic acid and the remaining composition components can be mixed in the equipment for use. When mixing is carried out outside the equipment, it can be mixed and used before starting the etching process.

[0026] (Advantages of the Invention)

[0027] When the etching composition according to the present invention is used in a wet etching process for a titanium nitride film and a tungsten film, it shows the remarkable effect of being able to maintain the etching rate of the titanium nitride film significantly faster, and at the same time being able to adjust the etching rate of the titanium nitride film to be the same as that of the tungsten film or the etching rate of the titanium nitride film to be up to 15 times faster than that of the tungsten film. Moreover, since the selectivity to underlying film materials such as polysilicon or silicon oxide films is also excellent, it can not only be widely applied to semiconductor manufacturing processes, but also shows the effect of being able to improve problems such as particle adsorption on the surface of the oxide film and poor removal of the nitride film.

[0028] Best Embodiment

[0029] Hereinafter, the present invention will be described in more detail.

[0030] First, an etching composition according to an embodiment of the present invention includes an inorganic acid, an oxidizing agent, an additive represented by Chemical Formula 1, and the balance of water, and is an etching liquid composition capable of maintaining the etching rate of a titanium nitride film significantly faster, and at the same time, capable of adjusting the etching selectivity of the titanium nitride film to a tungsten film to 1 to 15.

[0031] At this time, the inorganic acid as an etching accelerator may be any one selected from the group consisting of sulfuric acid, phosphoric acid, and mixtures thereof, and the content of the inorganic acid is 81 to 95% by weight based on the total weight of the etching liquid composition.

[0032] Among them, when the content of the inorganic acid is less than 81% by weight, there is a problem that the etching rate of the tungsten film is too fast, and when the content of the inorganic acid exceeds 95% by weight, there is a problem that the etching rates of both the titanium nitride film and the tungsten film are too slow (the slow etching rate of the titanium nitride film is the problem point). Therefore, the content of the inorganic acid is preferably 81 to 95% by weight based on the total weight of the etching liquid composition.

[0033] In addition, the oxidizing agent is any one selected from the group consisting of hydrogen peroxide, nitric acid, tert-butyl hydroperoxide, and 2-butane peroxide, and the content of the oxidizing agent is 0.1 to 3% by weight based on the total weight of the etching liquid composition.

[0034] At this time, when the content of the oxidizing agent is less than 0.1% by weight, there is a problem that the etching rates of both the titanium nitride film and the tungsten film are too slow (the slow etching rate of the titanium nitride film is the problem point), and when the content of the oxidizing agent exceeds 3% by weight, there is a problem that the etching rate of the tungsten film is too fast. Therefore, the content of the oxidizing agent is preferably 0.1 to 3% by weight based on the total weight of the etching liquid composition.

[0035] In addition, the additive is represented by the following Chemical Formula 1, and may include an alkylammonium salt or an alkyl alcohol ammonium salt containing a cationic surfactant, and may include an alkyl sulfate containing an anionic surfactant.

[0036] [[Chemical Formula 1]]

[0037]

[0038] Wherein, the additive can be selected from tetramethylammonium methyl sulfate, tributylmethylammonium methyl sulfate, dodecyltrimethylammonium methyl sulfate, behenyltrimethylammonium methyl sulfate, hexadecyltrimethylammonium methyl sulfate, triisononylmethylammonium methyl sulfate, heptadecyltrimethylammonium methyl sulfate, trimethyloctadecylammonium methyl sulfate, dimethyldioctadecylammonium methyl sulfate, butyldiisooctylmethylammonium methyl sulfate, tri-2-hydroxyethylmethylammonium methyl sulfate, ammonium sulfate, tetramethylammonium sulfate, tetraethylammonium sulfate, tetramethylammonium hydrogen sulfate, diethylammonium sulfate, ethylenedisulfate, tetraethylammonium hydrogen sulfate, triethylammonium sulfate, tetrabutylammonium sulfate, tetrabutylammonium hydrogen sulfate, methyl sulfate Any one of the group consisting of ammonium, trimethyl methyl ammonium sulfate, amyl ammonium sulfate, dodecyl ammonium sulfate, eicosyl ammonium sulfate, docosyl ammonium sulfate, isodecyl ammonium sulfate, 2-ethylhexyl ammonium sulfate, octyl ammonium sulfate, decyl ammonium sulfate, diethyl ammonium octyl sulfate, diethyl octadecyl ammonium sulfate, diethyl ammonium hexadecyl sulfate, ethyl trioctadecyl ammonium ethyl sulfate, dodecyl ethyl dimethyl ammonium ethyl sulfate, cyclohexyl diethyl ammonium dodecyl sulfate, 2-hydroxyethyl ammonium (2-ethylhexyl) sulfate, ethyl dimethyl octadecyl ammonium ethyl sulfate, 2-hydroxyethyl ammonium dodecyl sulfate, ethyl methyl dioctadecyl ammonium ethyl sulfate, diethyl ammonium octyl sulfate and mixtures thereof. The content of the additive represented by Chemical Formula 1 is 20 to 500 ppm by weight (0.002 to 0.05 wt%) relative to the total weight of the etching solution composition.

[0039] When the content of the additive is less than 20 wtppm (0.002 wt%), the etching rate of the tungsten film increases, so that the etching rate of the tungsten film is faster than the etching rate of the titanium nitride film, and then the etching selectivity ratio of the titanium nitride film to the tungsten film is less than 1. When the content of the additive is 500 wtppm (0.05 wt%) or more, the etching rates of both the tungsten film and the titanium nitride film are reduced (the etching rate of the titanium nitride film is too low, which is a problem). Therefore, the content of the additive is preferably 20 to 500 wtppm (0.002 to 0.05 wt%) relative to the total weight of the etching solution composition.

[0040] In order to adjust the etching selectivity of the titanium nitride film to the tungsten film required in the etching process, the etching solution composition can adjust the cation and anion structure of the additive represented by Chemical Formula 1, and accordingly, the etching selectivity of the titanium nitride film to the tungsten film can be adjusted to 1 to 15 (titanium nitride film etching amount: tungsten film etching amount = 1:1 to 15:1). In general, when the size of the cation is large, the etching selectivity of the titanium nitride film to the tungsten film rises to a large value above 1, and when the size of the anion is large, the etching selectivity of the titanium nitride film to the tungsten film is close to 1.

[0041] Finally, the etchant composition according to the present invention preferably contains: 81 to 95% by weight of an inorganic acid, 0.1 to 3% by weight of an oxidizing agent, 0.002 to 0.05% by weight of an additive represented by Chemical Formula 1, and the balance of water.

[0042] In addition, the temperature at which the etchant composition performs the etching process is preferably 50°C to 90°C.

[0043] In addition, since the etchant composition performs the etching process at 50°C to 90°C, in order to improve the stability of the etching process, the inorganic acid and the other components are preferably mixed and used in the equipment. When mixing is performed outside the equipment, it is preferably mixed at least before starting the etching process.

[0044] In addition, the process of simultaneously etching a titanium nitride film and a tungsten film using the etchant composition of the present invention can be carried out according to methods well known in the art, and examples include an immersion method through a batch process, or a method of performing the process sheet by sheet in a single wafer manner using a single device and spraying the etchant. In the etching process, other processes and other elements can be considered, and the temperature of the etchant can be changed as needed, but it is preferably 50°C to 90°C.

[0045] In addition, the method for etching a titanium nitride film and a tungsten film using the etchant composition of the present invention can be applied to a method for manufacturing an electronic device. The substrate of the film can be a semiconductor wafer, but the present invention is not limited thereto, and any substrate commonly used in the technical field of the present invention can be used. The titanium nitride film and the tungsten film deposited on the substrate can be formed by a conventional forming method.

[0046] Hereinafter, the present invention will be described in more detail using examples, comparative examples, and experimental examples. However, the following examples, comparative examples, experimental examples, and comparative experimental examples are intended to illustrate the present invention, and the present invention is not limited to the following examples, comparative examples, experimental examples, and comparative experimental examples, and various modifications and changes can be made. Detailed Description of the Invention

[0047] Examples 1 to 25 and Comparative Examples 1 to 12

[0048] The etchant compositions of the examples and comparative examples were put into each experimental beaker equipped with a magnetic bar at the composition ratios shown in Table 1, and then the upper part of the beaker was sealed, and then stirred at a speed of 400 rpm for 30 minutes at room temperature to prepare the compositions.

[0049] [Table 1]

[0050]

[0051]

[0052]

[0053] A-1: Sulfuric acid

[0054] A-2: Phosphoric acid

[0055] B-1: Hydrogen peroxide

[0056] B-2: Nitric acid

[0057] B-3: tert-Butyl hydroperoxide

[0058] B-4: 2-Butanone peroxide

[0059] C-1: Tetramethylammonium sulfate

[0060] C-2: Ethylenediammonium sulfate

[0061] C-3: Methylammonium sulfate

[0062] C-4: Dodecyltrimethylammonium sulfate

[0063] C-5: Ammonium dodecyl sulfate

[0064] C-6: Diethylammonium octyl sulfate

[0065] C-7: Ammonium sulfate

[0066] C-8: 2-Hydroxyethylammonium dodecyl sulfate

[0067] C-9: Ammonium phosphate

[0068] C-10: Ammonium acetate

[0069] D-1: Deionized water

[0070] [Experimental examples and comparative experimental examples]

[0071] Measurement of etching rates of titanium nitride film and tungsten film

[0072] Measure the performance of the etching solutions prepared in the above Examples 1 to 25 and Comparative Examples 1 to 12, and show the results in Experimental Examples 1 to 25 and Comparative Experimental Examples 1 to 12 in Table 2.

[0073] First, for measurement, prepare titanium nitride film and tungsten film wafers by deposition using the CVD method in the same manner as in the semiconductor manufacturing process.

[0074] Before starting the etching, measure the thickness before etching using a scanning electron microscope. Then, immerse the titanium nitride film and tungsten film wafers in an etching solution maintained at a temperature of 80°C in a quartz stirring tank stirred at a speed of 500 rpm for 30 seconds for the etching process.

[0075] After the etching is completed, wash with ultrapure water, and then use a drying device to completely dry the residual etching solution and moisture.

[0076] For the dried wafer sample, use a scanning electron microscope to measure the film thickness after etching. Accordingly, calculate the film thickness difference before and after etching, and thus determine the etching amount of titanium nitride film and tungsten film in 30 seconds at a given temperature.

[0077] [Table 2]

[0078]

[0079]

[0080] As shown in Table 2 above, by checking the etching amounts of the etching solutions used in Experimental Examples 1 to 25 at different temperatures for 30 seconds of etching, the etching amount of the titanium nitride film is more than that of tungsten at 80 °C. Thus, it not only shows a remarkable effect that the etching selectivity ratio of the titanium nitride film to the tungsten film is 1 to 15 (etching amount of titanium nitride film: etching amount of tungsten film = 1:1 to 15:1), but also the etching amount of the titanium nitride film is large. Therefore, it also has a remarkable effect of fast etching speed.

[0081] In contrast, by checking the results of Comparative Experimental Examples 1, 2, 3, 4, 6, 8, 9, 10, and 12, the etching amount of the titanium nitride film is less than that of tungsten at 80 °C, and the etching selectivity ratio is less than 1. Therefore, it cannot be used as the etching solution of the present invention.

[0082] In addition, in the case of Comparative Experimental Examples 5, 7, and 11, although the etching selectivity ratio is greater than 1, the etching amounts of both film qualities are very small. As a result, the etching speeds of both film qualities are significantly reduced. Finally, the etching speed of TiN is significantly reduced and the process time becomes long. Therefore, it cannot be used as the etching solution of the present invention.

[0083] That is, in Comparative Experimental Example 5, the selectivity ratio is 1.8:1, in Comparative Experimental Example 7, the selectivity ratio is 1:1, and in Comparative Experimental Example 11, the selectivity ratio is 2:1. Just from the etching selectivity ratio itself, it can be used as the etching solution of the present invention. However, in the case of such Comparative Experimental Examples 5, 7, and 11, the etching amount of TiN is 18, 2, and 16, which is significantly small. Accordingly, the etching speed of TiN is significantly low, and as a result, the process time becomes long. Therefore, finally, it cannot be used as the etching solution of the present invention.

[0084] Comprehensively evaluating the results of Examples 1 to 25, Comparative Examples 1 to 12, and the experimental examples and comparative experimental examples based thereon as described above, for the etchant compositions according to Examples 1 to 25, first, the etching amount of the titanium nitride film with respect to the tungsten film is large, so the etching rate of the titanium nitride film with respect to the tungsten film is fast, and thus the etching selectivity of the titanium nitride film to the tungsten film can be adjusted to 1 to 15 (etching amount of titanium nitride film: etching amount of tungsten film = 1:1 to 15:1). Second, at the same time, the etching amounts of both the titanium nitride film and the tungsten film are significantly large, so both have a fast etching rate. As a result, the etching rate of the titanium nitride film is significantly fast.

[0085] In addition, as a result of conducting experiments in the temperature range of 50 °C to 90 °C, it can be confirmed that it has the same tendency as when conducted at 80 °C.

[0086] Finally, the etchant composition according to an embodiment of the present invention includes: 81 to 95% by weight of an inorganic acid, 0.1 to 3% by weight of an oxidizing agent, 0.002 to 0.05% by weight of an additive represented by Chemical Formula 1, and the balance of water. It has been found that it exhibits the following remarkable effects: for various wet etching processes according to semiconductor manufacturing processes, the etching rate of the titanium nitride film can be maintained significantly fast, and at the same time, the etching selectivity of the titanium nitride film to the tungsten film can be adjusted to 1 to 15 (etching amount of titanium nitride film: etching amount of tungsten film = 1:1 to 15:1) for use.

[0087] As described above, specific parts of the content of the present invention have been described in detail. For those of ordinary skill in the art, it is obvious that these specific techniques are only preferred embodiments, and the scope of the present invention is not limited thereby. Therefore, the substantial scope of the present invention will be defined by the appended claims and their equivalents.

Claims

1. An etching solution composition, wherein, The composition consists of the following components: a) 81 to 95% by weight of an inorganic acid, relative to the total weight of the etchant composition, which inorganic acid is any one selected from the group consisting of sulfuric acid, phosphoric acid, or a mixture thereof; b) 0.1 to 3% by weight of an oxidizing agent, relative to the total weight of the etchant composition, which oxidizing agent is one selected from the group consisting of hydrogen peroxide, nitric acid, tert-butyl hydroperoxide, and 2-butane peroxide; c) 0.002 to 0.05% by weight of an additive, relative to the total weight of the etchant composition, which additive is dodecyltrimethylammonium sulfate; and d) the balance of water, e) the etching selectivity of the titanium nitride film to the tungsten film is 11.7 to 14.

5.

2. An etching method for a laminate of a titanium nitride film and a tungsten film, wherein, Including: The step of etching a laminate of a titanium nitride film and a tungsten film using the etchant composition according to claim 1.

3. The method for etching a laminate of a titanium nitride film and a tungsten film according to claim 2, characterized in that the step of etching the laminate of the titanium nitride film and the tungsten film is carried out at a temperature of 50°C to 90°C.

4. The method for etching a laminate of a titanium nitride film and a tungsten film according to claim 3, characterized in that in the step of etching the laminate of the titanium nitride film and the tungsten film, the inorganic acid and the remaining components in the etchant composition are mixed and used in an etching apparatus.

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